Feasibility study on incorporating waste from waterproofing membranes into asphalt mixtures

Abstract: The construction sector needs to find more sustainable production patterns based on the circular economy principle. The industry of bituminous membranes for waterproofing systems faces a significant dilemma regarding waste disposal since incineration and landfills are no longer acceptable. To solve this problem, a feasibility study was developed to analyse the incorporation of membrane waste into conventional hot mix asphalt through the dry process. There have yet to be any known studies on the valorisation of this type of waste in asphalt mixtures, and this paper will cover the gap. The methodology used in the study consisted of an experimental programme in the laboratory: (1) to assess the mechanical behaviour of hot asphalt mixture for the base course; (2) to evaluate the efficiency of the dry process of waste incorporation. The paper will present results on Marshall resistance, resistance to permanent deformation, sensitivity to water and stiffness for different test conditions. Complementary tests were carried out on the bitumen modified by the membrane waste (penetration, softening temperature and dynamic viscosity). The results showed that it was feasible to include membrane waste without affecting the performance of asphalt mixtures. In addition, it was possible to confirm the acceptable efficiency of the dry process using a simple methodology. However, it will still be necessary to develop an easy and efficient process for processing membrane waste (grinding) to further improve its incorporation and digestion into the asphalt mixture on an industrial scale.